Abstracts

Landau-Kleffner syndrome (KLS) is characterized by normal speech acquisition followed by epileptic seizures and acquired aphasia in childhood caused by receptive and expressive language deterioration regarding verbal and non-verbal sounds, with variable long-term evolution. EEG abnormalities are seen especially during sleep in temporal areas, where verbal language and acoustic information is processed. Since the hemispheric dominance is not definitive at this time, the aphasia probably is caused by bilateral involvement that some times can not be detected. The aim is to describe acoustic neurophysiologic findings in four patients with LKS, aged 19 (Pt 1, Pt 2), 14 (Pt 3) and 12 (Pt 4) yrs., and to correlate with electroencephalografic aspects. EEG was performed during the acute phase and a control EEG, immittance acoustic measurements (IAM), basic audiometry (BA), and auditory evoked responses with brainstem, mean and long latencies studies (ABR, MLR, Cognitive Potential-P300) were done 7 to 13 yrs after the onset. EEG showed paroxysmal discharges in acute phase in all patients, in left central region in one (pt 3), and in bilateral perisylvian area in three. Language outcome revealed severe receptive and expressive impairment in only one patient (pt 4), who presented severe phonemic substitutions, with impact on social and academic levels, and the other three evolved with normal language, school grade and interpersonal skills. EEG during evolution was normal in all. Audiologic evaluation revealed normal IAM, BA and ABR results, with different findings in MLR, which was normal in one (pt 2), and showed electrode effect in left hemisphere in two, and in right in one (pt 3). P300 latency was normal in one (pt 2) and delayed in three, one of them with contralateral abnormality compared to the EEG focal discharges at onset of the disease (pt 3). Although most patients with LKS have bilateral cortical involvement, probably triggered by a unique focal dysfunctional area, detected by EEG during the acute phase, some with unilateral evidence of cortical/subcortical impairment may in fact have bilateral pathology, that explains the aphasia in young children and may be revealed by other methods such as auditory evoked potentials . (Supported by FAPESP.)